This invention relates to dryers for extracting moisture from wet goods, and in particular to a heat recirculating dryer having improved efficiency and recirculating capabilities.
Dryers of the nature of the present invention are typically utilized in commercial laundering facilities where large quantities of wet linens are dried in batches of up to several hundred pounds. Wet linens are delivered to the dryer in large "cakes" such as those illustrated in U.S. Pat. No. 4,509,275, the disclosure of which is incorporated herein by reference.
A typical commercial dryer includes a tumbler cylinder mounted for rotation about a horizontal axis and which has an open side through which cakes of linens are inserted and the dried goods are removed. The cylinder is housed within a shell and is rotated about the horizontal axis. The shell is pivoted at either its bottom or its top (as illustrated in referenced U.S. Pat. No. 4,509,275), so that the shell can be tipped to permit dry linens to be removed therefrom.
As energy costs have escalated, it has become particularly important that the efficiency of the dryer be as high as possible. Thus, dryers have begun incorporating recirculating systems so that a portion of the air withdrawn from the tumbler cylinder is recirculated back to the dryer so that the eventually-exhausted air is as close as possible to the dew point, thus utilizing to the extent possible the moisture trapping capability of the air introduced into the tumbler cylinder for drying of the goods therewithin. The means of recirculation of such prior dryers has typically been a damper located in the exhaust duct to cause a portion of the air to be recirculated directly back into the tumbler cylinder. By judicious adjustment of the damper, greater or smaller portions of the recirculated air can be reintroduced into the tumbler cylinder.